The present invention relates to an endoscope system, a method for operating endoscope system and the like.
An endoscope system has been widely used that applies illumination light to tissue inside a body cavity, and allows the user to perform diagnosis and procedures using an image obtained by capturing reflected light from the tissue. An image sensor (e.g., CCD image sensor or CMOS image sensor), and an objective lens that optically forms an image of the object are provided on the end of the insertion section. A wide-angle objective lens is normally used as the objective lens of the endoscope in order to prevent a situation in which a lesion area is missed. For example, an objective lens having an angle of view of 170° has been used.
A wider field of view can be observed by utilizing an objective lens that forms an image of the side field of view of the end of the insertion section (see JP-A-2010-169792, for example).
JP-A-2002-263064 discloses a dimming method that calculates the average luminance of the pixels within the effective area enclosed by the mask shape of the scope, and maintains the brightness of the object image. JP-A-9-98943 discloses a method that is adapted for an endoscope system that acquires a wide-angle image, and disposes a light guide on at least three sides of the image plane of the image sensor to provide an appropriate intensity distribution.